Safety device for hypodermic needle or the like

ABSTRACT

A safety device for a hypodermic needle or for a similar instrument used in the clinical puncture of the skin comprises a sheath (6, 25 or 32) adapted to be connected to the needle (5, 21 or 33) or to a support (4 or 31) for the needle. The sheath is so connected in a first position (FIG. 1A, 2A, or 3A) which permits normal use of the needle and can be placed, by movement relative to the needle (FIG. 1B or 3B) or by folding upon itself (FIGS. 2B and 2C) in a second position in which the needle is encapsulated by the sheath. The sheath is retained in that second position, for example by a projection (9, 27 or 35) extending into a slot (10 or 36) or through an aperture (28).

The present invention is a safety device for a hypodermic needle orsimilar instrument used in the clinical puncture of the skin.

The taking of blood samples from persons in hospitals, health centres orother clinical areas is a routine medical procedure, as is the injectionof pharmaceutical preparations or biological materials. However, manyincidents have been reported in the press and in medical journals ofclinical operators subsequently accidentally wounding themselves orother persons with the needle and thereby either transmitting a diseaseor causing chemical or biological poisoning.

There is a clear need for a device which permits the disposal of ahypodermic needle or such instrument in a manner which protects theclinical operator, observers of the clinical procedure and all otherpersons concerned, including the general public, from accidentalwounding.

It is an object of the present invention to provide such a device.

The safety device according to the invention for a hypodermic needle orsimilar instrument comprises a sheath, adapted to be connected to saidneedle or other instrument or to a support therefor in a first positionwhich permits normal use of said needle or other instrument and to beplaceable, by movement relative to the needle or other instrument or byfolding upon itself, in a second position in which the needle or otherinstrument is encapsulated by the sheath and the sheath is retained inthat second position.

As indicated, the safety device of the present invention is generallyapplicable to the protection of puncturing instruments typified byhypodermic needles, although among such instruments hypodermic needlesare by far the most widely used. For example, the device may be appliedto the protection of biopsy needles, winged needles, that is needlesprovided with lateral attachments to enable them to be affixed to theskin surface as by adhesive tape, and to intravenous cannulas and lumbarpuncture needles. For convenience, the invention is hereinafterdescribed specifically as applied to "needles", in particular hypodermicneedles, but it is emphasised that the invention is not to be limitedthereby.

The sheath is adapted to be attached to the needle or to a support forthe needle but may be provided separately from the needle, to beattached to the needle or support at the point of use, either before orafter the needle has actually been used. It is much preferred that suchseparate sheaths be attached before use, so that the needle may be morereadily encapsulated immediately after it has been used. However, thesheath according to the present invention is preferably and convenientlysupplied already attached to the needle. In particular, it is preferablyattached either irremovably or in a way which makes its removaldifficult. For example, the sheath may be adhered to the needle or to asupport for the needle or may be clipped to the needle or support.

When the needle is designed for use without a syringe or remote from anassociated syringe, to which it is then linked by a flexible tube, thenthe sheath is preferably secured direct to the needle. The sheath maythen conveniently incorporate one or more parts which are foldablerelative to the body of the sheath and thereby to encapsulate theneedle.

When the needle, on the other hand, is mounted upon a housing designedto be attached to a syringe barrel or luer connector, then the sheathmay advantageously be secured to the housing. The sheath may then becapable of movement relative to the housing in a direction which has acomponent parallel to the length of the needle, so that the sheath maybe moved along the length of the needle until the latter is fullyencapsulated. This relative movement of sheath and housing may forexample be a linear sliding movement or a spiral movement, as moreparticularly exemplified hereinafter in FIGS. 3A and 3B of the drawings.

Such relative movement of sheath and housing may be determined by one ormore liner or spiral grooves or channels in the housing engaging one ormore lugs or other projections on the sheath--or grooves or channels inthe sheath engaging projections on the housing.

In the second position of the sheath, in which the needle isencapsulated, the sheath is retained against further movement relativeto the needle. That retaining of the sheath is preferably irreversibleor reversible only with difficulty. For example, one or more lugs orother projections on one of the relatively movable components may engageone or more apertures or slots in the other component, preferably underthe pressure of a natural resilience in at least one of the componentsor under pressure from one or more springs.

The sheath may advantageously and conveniently be made from a resilientplastics material, for example polypropylene, and the housings may bemade from the same, or a similar, material.

The invention will now be further described with reference to theaccompanying drawings, wherein:

FIG. 1A is a sectional view of a first embodiment of the safety deviceaccording to the present invention, in a position in which the needlemay be used normally;

FIG. 1B is an enlarged detailed view of the circle portion of FIG. 1A;

FIG. 2A is a view corresponding to that of FIG. 1A but with the sheathmoved to encapsulate the needle; and

FIG. 2B is an enlarged detailed view of the circle portion of FIG. 2A.

FIG. 3 is a sectional view of a second embodiment of the safety deviceaccording to the present invention, in a position in which the needlemay be used normally;

FIG. 4A is a view corresponding to that of FIG. 3 but with the sheathfolded to encapsulate the needle;

FIG. 4B is an enlarged view of the circled portion of FIG. 4A;

FIG. 4C is a plan view of the device in the position shown in FIG. 4A;

FIG. 5A is a view, partly in section, of a third embodiment of thesafety device according to the present invention, in a position in whichthe needle may be used normally; and

FIG. 5B is a view corresponding to that of FIG. 5A but with the sheathmoved to encapsulate the needle;

FIG. 5C is an enlarged view of the circled portion of FIG. 5B.

The embodiment of the invention shown in FIGS. 1A and 1B comprises aneedle housing 4 in the form of a plastics moulding carrying a needle 5and, slidably supported upon the housing 4, a plastics sheath 6incorporating a thumbguard 7 integral therewith. Also incorporated inthe housing 4 and running lengthwise, is a channel 8. The sheath 6incorporates a self-springed spigot 9 which slides along the channel 8,as shown in more detail in the enlarged inset. When the sheath travelsto the end of the channel 8, the self-springed spigot 9 drops into asmall "well" 10, thus locking the sliding sheath in position. The lengthof the sheath is such that, when it is locked in position, the sharp endof the needle is completely enclosed by the sheath, as shown in FIG. 1B.

The housing 4 is designed to mate with any standard syringe barrel orluer connector. After use, the protective sheath is extended into thelocked position, thus encapsulating the needle in a safe manner.

The embodiment of the invention shown in FIGS. 3-4C is designed to allowencapsulation of a hypodermic needle 21 which is tethered to a syringeby an extension tube 22. The needle 21 is sandwiched between twoplastics mouldings or pressings 23,24 which together form a sheath 25. Apart 26 of the sheath 25 is permanently attached to the hypodermicneedle. At points 23a and 24a the plastic is formed in a manner whichallows the free ends of members 23 and 24 to hinge as indicated. Near toits outer end, the member 23 carries two spigots 27, which are designedto mate with holes 28 in the member 24 (when the sheath is in its foldedposition) and lock the sheath securely around the needle 21.

The third embodiment of the invention, as illustrated in FIGS. 5A-5C,comprises a needle housing 31 in the form of a plastics moulding, aplastics sheath 32 which is free to rotate thereon and a needle 33.Impressed into the housing 31 is a helical groove 34 extending from nearthe end of the housing 31 which is distal to the needle 33 towards theneedle. The sheath 32 has a self-springed spigot 35 which fits into, andis free to move along, the helical groove 34. As shown in FIG. 5B,rotation of the sheath 32 in a clockwise direction (viewed from therear) will result in a forward motion causing the sheath to encapsulatethe needle 33. At the end of its travel the springed spigot 35 dropsinto a "well" 36 thereby locking the sheath in position. The length ofthe sheath 32 is such that when it has reached this locked position theneedle is completely encapsulated and withdrawn beyond the orifice 37 inthe outer end of the sheath.

The device shown in FIGS. 5A and 5B is designed to mate with anystandard syringe barrel or luer connector. After use, the protectivesheath is placed in position by applying a twisting force to the sheath.To facilitate the application of this twisting force, a raised section38 may be incorporated into the sheath's surface.

This form of the invention may be fabricated with one or more helicalgrooves, which may extend in a clockwise or anti-clockwise direction.For greater mechanical strength and stability, a double helix may bepreferred.

We claim:
 1. For use with clinical apparatus operably applied to a patent by way of skin puncture, a disposable non-reusable hypodermic needle assembly comprising:a needle support housing having a connector formation for removable attachment with said apparatus; a hypodermic needle supported by said housing for communication with said apparatus by way of said formation, one end portion of said needle projecting from said housing remotely from said formation; a sheath surrounding said housing and mounted thereon for movement in the longitudinal direction of said needle from a first position nearer to said formation and in which first position said needle one end portion is exposed to effect said puncture, to a second position further from said formation and in which second position said needle one end portion is enclosed within said sheath; a strop mechanism effective to constrain said sheath against movement from said first position towards and around said apparatus; and locking means irreversibly automatically operable to secure said sheath in said second position upon said movement into such position, said locking means having two elements respectively located on the interior of said sheath and on a portion of said needle housing covered by said sheath in said second position so that said locking means is, when operated, wholly between said sheath and said housing.
 2. An assembly according to claim 1 wherein, to serve as said stop mechanism, said housing has a portion with external dimensions transversely of said longitudinal direction which are enlarged relative to the remainder of the housings, and said sheath has lesser corresponding internal transverse dimensions surrounding said housing than said portion.
 3. An assembly according to claim 2 wherein said housing connector formation includes said transversely enlarged portion.
 4. An assembly according to claim 1 comprising guide means on said housing to guide said sheath between said first and second positions.
 5. An assembly according to claim 4 wherein said guide means comprises a channel formed in one of said housing and sheath to extend in said longitudinal direction, and a projection from the other one of said housing and sheath, said channel and projection being mutually engaged.
 6. An assembly according to claim 5 wherein said locking means comprises a well formed in one end of said channel to receive said projection in irreversible engagement therein.
 7. An assembly according to claim 6 wherein, to serve as said stop mechanism, the other end of said channel is closed.
 8. An assembly according to claim 1 wherein said locking means comprises a projection from one of said housing and sheath, and a well formed in the other of said housing and sheath to receive said projection in irreversible engagement therein.
 9. Clinical apparatus for application to a patient by way of skin puncture, comprising:a chamber operable in one of two modes respectively to apply and draw fluent material to and from said patient; a non-reusable hypodermic needle assembly including a support housing attached with said chamber, and a hypodermic needle connected with said housing for communication with said chamber, said needle having one end portion projecting from said housing remotely from said chamber; and a sheath surrounding said assembly and mounted thereon for limited movement in the longitudinal direction of said needle from a first position to a second position, said first position being removed from but nearer to said chamber to expose said needle one end portion, and said second position being further from said chamber to cover said needle one end portion; said assembly and sheath being provided with respective elements of a locking mechanism means irreversibly automatically cooperable to secure said sheath in said second position upon said movement into such position, said elements being respectively located on the interior of said sheath and on a portion of said needle assembly covered by said sheath in said second position so that said elements are, when operated, wholly between said sheath and said assembly.
 10. Apparatus according to claim 9 wherein said locking means elements comprise a projection and a well to receive said projection in irreversible engagement therein. 